Mumbai (Bombay) weather in September

Regulars are split on this month more than the general warnings suggest - most call it too hot and humid to recommend, citing the city's island geography as the reason humidity compounds the heat so heavily, while others point out the daytime high isn't far off Toronto's own summer peak and that air-conditioned rooms make it manageable. Our row backs the intensity, 34C reading as a genuinely severe 39C at 72 percent humidity, over 24.7C nights, with rain essentially absent, 0.4mm and zero rainy days. Regulars note evenings and early mornings are meaningfully more bearable than the midday stretch, and that locals routinely go about their day regardless, umbrella or scarf as sun protection rather than for rain. The sea holds 29.8C. The record: 11.7 hours of sun, an 18.4 kph wind and AQI 110.

March opens the pre-monsoon hot season here, which regulars date roughly mid-March to mid-June and rate progressively worse as it goes - April and May are the months to actively avoid, with March the comparatively gentler start of that run. Our row already shows real heat, 33.7C reading as 37C, though the air is genuinely dry for this city at 64.5 percent humidity, before the monsoon arrives around the 15th of June and the moisture returns with it. Rain has essentially stopped, 0.9mm across barely any days. The board's clear preference is the November-to-February window well before this, so a March trip is arriving as that better season closes. The sea is 27.9C. The record: a dew point of 18C, 11.1 hours of sun, a 17.6 kph wind and AQI 139.

Mumbai-forum threads rate December as one of the best months on the calendar, weather-wise - part of the November-to-February window regulars point to as the pleasant, dry season, the antidote to the sticky, stormy stretch that comes before it. Afternoons are still hot and humid, though posters say not too bad, and nights and early mornings turn genuinely pleasant. The record backs the 'not too bad' read on humidity more than the 'pleasant' one on heat: 32.2C days feeling like 35C, 19.4C nights, essentially none at one day for the whole month, and a 26.9C sea. The number forum chat skips past: AQI runs 154 here, one of the worst months of Mumbai's year for air, the trade-off for the dry season's still, cloud-free air.

India-forum threads put the comfortable travel window at November through February, with November described as better than the tail of September and the start of peak tourist season - so book ahead. Mumbai's own November record is the payoff: 34.3C days and 21.7C nights, humidity around 67 percent, ten hours of sun a day, a 28.5C sea, and almost no precipitation at all, under two days on average, as the year turns toward winter. One trade-off comes with the calm: November carries some of the city's worst air of the year, with an AQI near 172, so plan outdoor sightseeing for mornings rather than the hazy afternoon.